Various anchoring devices are known, which are designed to be forcibly driven into a hole that has been drilled into a body of concrete, masonry, or like material so as to become anchored within the hole. Concrete and masonry are characterized by means of high compressive strength and, therefore, exhibit very little yield when compressed. Typically, such an anchoring device has a head, which is adapted to mount an external element, and a shank, which is integral with the head. When the head is struck by means of a hammer or by means of a driving ram of a powered tool, the shank is driven forcibly into the hole, within which the shank becomes anchored.
Two-piece anchoring devices are known, in which sleeves or other elements are expanded when such devices are driven into the hole. One-piece anchoring devices are known, moreover, and are preferred in many applications. Typically, a one-piece anchoring device has a shank portion that is deformed when such device is driven into a hole. The deformed portion anchors the shank within the hole.
A variation of a one-piece anchoring device is disclosed in Giannuzzi U.S. Pat. No. 4,828,445. As disclosed therein, the anchoring device has a resilient shank, which is shaped with one or more undulations near its distal end, and which is smooth-surfaced.
Other anchoring devices of related interest are disclosed in Carroll U.S. Pat. No. 1,574,790, French Patent No. 2,468,024, German Patent Application No. 915,732, German Patent Application No. 3,620,372, and Japanese Patent Application (Laid-Open Publication) No. 55-122,918.
An improved, one-piece anchoring device is disclosed in a copending patent application, U.S. Ser. No. 07/459,491, which was filed by Martin J. Nilsen, and which is assigned commonly herewith.
This invention is addressed to improvements in an anchoring device exemplified by the anchoring device disclosed in the copending application noted above.